Contrast nephropathy is a major cause of morbidity in hospitalized patients. Although there are identified risk factors for this development, there is no method by which one can accurately predict which patients receiving contrast agents will develop contrast nephropathy. In this study, we propose to test a system that, hypothetically, will be able to detect the onset of contrast nephropathy within 8 hours after receiving contrast media. Early identification may prevent or lessen the severity of contrast nephropathy.